看到群里有人问普通用户访问基表的问题，测试下如下： X$基表可以通过创建视图，再对视图创建同义词方式、授权的方式来实现普通用户可以访问基表。 当然了普通用户访基表也是没道理的，理论上没必要，权限控制上也应该是不允许的。此处不考虑合理性，就此问

看到群里有人问普通用户访问基表的问题，测试下如下：

X$基表可以通过创建视图，再对视图创建同义词方式、授权的方式来实现普通用户可以访问基表。

当然了普通用户访基表也是没道理的，理论上没必要，权限控制上也应该是不允许的。此处不考虑合理性，就此问题进行实验。

1.直接对X$基表创建同义词，其它用户无法实现访问。

SQL> show user
USER is "SYS"
SQL> select count(*) from sys.x$kcbwds;

 COUNT(*)
----------
 8

SQL> CREATE PUBLIC SYNONYM kcbwds FOR sys.x$kcbwds;

Synonym created.

SQL> grant select on sys.x$kcbwds to bys;
grant select on sys.x$kcbwds to bys
 *
ERROR at line 1:
ORA-02030: can only select from fixed tables/views
----------
SQL> show user
USER is "BYS"
SQL> select count(*) from sys.x$kcbwds;
select count(*) from sys.x$kcbwds
 *
ERROR at line 1:
ORA-00942: table or view does not exist


SQL> select count(*) from kcbwds;
select count(*) from kcbwds
 *
ERROR at line 1:
ORA-00942: table or view does not exist

SQL> show user
USER is "SYS"
SQL> select count(*) from x$kcbwds;

 COUNT(*)
----------
 8
SQL> create view testa as select * from sys.x$kcbwds;

View created.

SQL> grant select on sys.testa to bys;

Grant succeeded.

SQL> conn bys/bys
Connected.
SQL> show user
USER is "BYS"
SQL> select count(*) from sys.testa;

 COUNT(*)
----------
 8
SQL> desc sys.testa
 Name Null? Type
 ----------------------------------------- -------- ----------------------------
 ADDR RAW(4)
 INDX NUMBER
 INST_ID NUMBER
 SET_ID NUMBER
 POOL_ID NUMBER
 DBWR_NUM NUMBER
 BLK_SIZE NUMBER
后面省略。。

SQL> CREATE PUBLIC SYNONYM testb FOR sys.testa;

Synonym created.

SQL> show user
USER is "SYS"
SQL> conn / as sysdba
Connected.
SQL> conn bys/bys
Connected.
SQL> select count(*) from testb;

 COUNT(*)
----------
 8